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From: jon_sree@world.std.com (Jon Sreekanth)
Newsgroups: comp.dcom.telecom
Subject: Re: Pulse-Mode Frequencies?
Message-ID: <15962@accuvax.nwu.edu>
Date: 10 Jan 91 14:55:37 GMT
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In article <15852@accuvax.nwu.edu> mitel!Software!meier@uunet.uu.net
(Rolf Meier) writes:

   Some fast operators are specified to work up to 20 pps.

I have a Uniden phone that I bought around 1986, and it has a three
position switch : DTMF, 10pps pulse, 20pps pulse. I've not had any
problems using 20pps in CA and MA (but in well populated suburban
areas).

   Who cares about dial pulsing any more anyway?

I understand it's still widely used outside North America.

On this topic, why do many voice mail and other phone operated
services insist on users having DTMF phones ? Is it really hard to
detect pulse mode digits? I can see that the low numbers might be a
problem, (can't distinguish it from a noise pulse), but if one saw
five to ten regularly spaced pulses, isn't that adequate for
recognition?

I've seen AT&T answering machines which say on the box that they
work with pulse phones (at the remote end, for checking one's
messages).  I haven't played with them. Does anyone know how they
work, or how reliable the detection is ?


Regards, 


Jon Sreekanth

Assabet Valley Microsystems			Fax and PC products
346 Lincoln St #722, Marlboro, MA 01752		508-562-0722
jon_sree@world.std.com


[Moderator's Note: The old Unitel (United Airlines) internal phone
network was able to recognize pulse dialing on the in-dial to their
call-extender here several years ago. Don't ask me how they did it. I
did note at the time that tone signals were more reliable.   PAT]